The present disclosure relates to the subject matter disclosed in German patent application No. 198 48 715.0 of Oct. 22, 1998, the entire specification of which is incorporated herein by reference.
The invention relates to an osteosynthetic holding system with bone anchoring elements comprising two receptacles arranged alongside each other for one holding bar each and a clamping element, which in the tightened state thereof clamps the two holding bars against the receptacles, and with blocking elements which together with the clamping element in the tightened state thereof constrict the access to the receptacles in a direction transverse to the longitudinal direction of the holding bars such that the holding bars no longer fit through the access.
Such osteosynthetic holding systems are used for fixing the position of bone parts relative to one another. Bone anchoring elements, for example, in the form of bone screws, hooks, etc., are inserted into the bone parts to be fixed, and these bone anchoring elements are fixed relative to one another via holding bars.
In osteosynthetic holding systems, it is known to join the bone anchoring elements together by two parallel bars which are inserted into receptacles on the bone anchoring elements and are clamped against these receptacles by clamping elements on the bone anchoring elements. With the clamping element in the released state, it is thus possible, to bring the bone anchoring elements into the desired position relative to each other and using two bars to then fix this position in a very stable and lasting manner by tightening the clamping element.
In order to already fix the holding bars at least loosely in their position in the receptacles before tightening the clamping elements, it is, furthermore, known to provide the receptacles with blocking elements which make the access to the receptacles, which is determined by these blocking elements, on the one hand, and by the clamping element, on the other hand, so narrow that the holding bars are held undetachably in the receptacle when the clamping element is not completely released but is already close to the end position in which the clamping occurs. Therefore, only when the clamping element is completely released can the holding bars be removed from or inserted into the receptacle.
This narrowing of the access also serves to ensure that the holding bars remain securely in the clamped position in the receptacle.
Thus, in the known holding systems of this kind both holding bars are inserted before tightening the clamping elements. The clamping elements are then tightened up to a position in which the holding bars are held undetachably, but are not yet clamped against the receptacle. If, in this situation, work has still to be done on the bone fragments or the bone anchoring elements have to be adjusted, this may obstruct the operator to a certain extent as both holding bars are inserted in the receptacles and may, under certain circumstances, cover the operating area.
The object of the invention is to design an osteosynthetic holding system of the generic kind so as to prevent an obstruction by the two undetachably inserted holding bars prior to the final tightening of the holding system.